The invention relates to a process for the production of a cover unit with a seal for vehicle roofs, in which at least one cover part and one cover support are placed in a mold comprising an upper part and a lower part, and with mold closed, an elastomer is introduced, which fills edge gaps between the cover part and the cover support, and connects them into a cover unit. Furthermore, a peripheral seal can be provided on this cover unit. The invention further relates to a cover unit for vehicle roofs as produced by such a method.
A process for the production of an assembly comprising a cover and seal for vehicle roofs of the above-mentioned type is known from German Offenlegungsschrift DE 37 42 719 A1. In this process, a cover part, such as a glass cover, and a cover support, together with a seal having a sealing element having an inwardly directed projection, are inserted in a mold comprising an upper part and a lower part so that the seal is applied with its outside edge against the inside edge of the mold, the projection projects between the cover support, and the cover part and edge gaps remain open between the outside edges of the cover part and cover support as well as inside wall parts of the sealing element, and these gaps are connected to one another through holes in the projection of the seal. Then, the mold is closed, and an elastomer injected into the mold so as to fill the edge gaps and mutually connect the cover part, cover support and seal. Thus in this production process , a unit of a cover part, cover support and a seal is formed by the elastomer used as a molding compound. In an assembly produced in this way, the adherence to narrow tolerances in the outside dimensions of the produced assembly causes difficulties, since the sealing element of the inserted seal rest against a wall of the mold and therefore, can be deformed when introducing the elastomer, so that great tolerance fluctuations in the outside dimensions can hardly can be avoided. Further, the mold for the production of the assembly has several undercuts, as a result of which the production of the mold becomes more expensive. Especially when the seal is damaged or becomes worn with time with use of the assembly as a cover for a vehicle roof, the entire assembly has to be replaced, even though only the peripheral seal or the edge gap seal would, otherwise, require replacement. The assembly is, therefore, not very easy to maintain.
A rigid cover for a vehicle roof is known from German Patent 35 06 009 C2, in which a cover plate and a reinforcing frame placed underneath it are molded into a one-piece continuous plastic frame to minimize the production tolerances of the outside measurements of a cover for vehicle roofs. This plastic frame, at the same time, forms an upper frame and has molded-on fastening elements for a seal or a sealing element. The procedure described there is relatively complicated because, after the molding process, the seal has to be introduced in a groove formed in the plastic frame. Further, the plastic frame projects over the cover plate, which is disadvantageous for aesthetic reasons, as well as with respect to wind noises and dirt accumulations. Apart from that, the mold also requires several undercuts, which contribute to a cost increase in the production of the mold. Further, in this case, relatively great tolerance fluctuations in the outside dimensions of such a rigid cover can also hardly be avoided, since at least the tolerances of the sealing receptacle area and the tolerances of the seal are cumulative.